With the rapid development of display technology, touch panels have gradually spread throughout people's lives. Currently, the touch panels may be classified by construction into: add on mode touch panel, on cell touch panel, and in cell touch panel. Wherein, as for the add on mode touch panel, the touch panel and the liquid crystal display screen are manufactured separately and then bonded together to provide a liquid crystal display screen with touch capabilities. The add on mode touch panel has defects such as higher production cost, low light transmittance, and thicker module. As for the in cell touch panel, due to the fact that the touch electrode of the touch panel is embedded inside the liquid crystal display screen, the entire module can be thinned and the production cost of the touch panel can be greatly reduced, thus being favored by the major panel manufacturers.
An existing capacitive in cell touch panel is achieved by additionally providing touch scanning lines and touch sensing lines directly on an existing thin film transistor (TFT) array substrate, that is, two layers of strip-shaped ITO (Indium Tin Oxides) electrodes, which are intersected on different planes, are made on the surface of the TFT array substrate, these two layers of ITO electrodes function as the touch driving lines and the touch sensing lines of the touch panel respectively, and an inductive capacitor is formed at the intersection of the two layers of ITO electrodes on different planes. The operation process of the touch panel is as follows: when a touch driving signal is applied to the ITO electrode functioning as touch driving lines, a voltage signal from the touch sensing line coupled via the inductive capacitor is detected; during this process, when a human body contacts the touch panel, electric field of the human body will act on the inductive capacitor no that capacitance of the inductive capacitor will change, which in turn change the voltage signal coupled from the touch sensing line. Based on the change of the voltage signal, location of the touch point can be determined.
When designing the above capacitive in cell touch panel, it is necessary to add a new film on the existing TFT array substrate, which will complicate the structure of the TFT array substrate; new processes also need to be added when manufacturing the TFT array substrate, which will increase the production cost; and when designing the above capacitive in cell touch panel, it is necessary to utilize two driving chips (IC) simultaneously no as to achieve touch driving and display driving respectively, which will increase the cost.